Intramuscular injection devices

ABSTRACT

An intramuscular injection ampoule of the contained-needle type and a combination of such an ampoule with a so-called &#39;&#39;&#39;&#39;applicator&#39;&#39;&#39;&#39; for actuating the ampoule to make injections are disclosed. The ampoule has at least one cylindrical, medicamentcontaining chamber and a plunger closing one end thereof. A hollow needle is fixed to the plunger and is initially contained within such a chamber. The other end of the ampoule is sealed by a diaphragm. The ampoule is only partially filled with a medicament so that the needle may be advanced through the diaphragm to a preinjection position. The ampoule is then positioned in an applicator and is retained therein by releasable spring clips. A spring-loaded force-applying member drives the ampoule past the clips so that the needle enters the patient&#39;&#39;s muscle and then the plunger is moved relative to the cylinder to inject the medicament.

United States Patent 1191 Hurschman June 28, 1974 INTRAMUSCULAR INJECTION DEVICES [75] Inventor: Alfred A. I-Iurschman, Streetsboro, f EXaml'.1er Rlchard Gaudet Ohio Assistant Examiner-J. C. McGowan Attorney, Agent, or FirmMcNenny, Farrmgton, [73] Assignee: Ampoules, Inc., Macedonia, Ohio P am & Gordon [22] Filed: Aug. 24, 1972 21 Appl. No.: 283,505 [57] ABSTRACT Rdated Appncafion Data An intramuscular injection ampoule of the containedneedle type and a combination of such an ampoule [62] '9 with a so-called applicator for actuating the ampoule to make injections are disclosed The ampoule has at least one cylindrical, medicament-containing 'i 128/218 chamber and a Plunger closing one end thereof. A hol- [58] Fie'ld R 218 D low needle is fixed to the plunger and is initially con- ]28 D A F 173* 6 tained within such a chamber. The other end of the ampoule is sealed by a diaphragm. The ampoule is only partially filled with a medicament so that the nee- [56] References Cited dle may be advanced through the diaphragm to a UNITED STATES PATENTS preinjection position. The ampoule is then positioned 7 2,472,116 6/1949 Maynes 128/218 F in an applicator and is retained therein by releasable 2,704,072 3/ 1955 Sarnoff Spring c]ips A i l d d f l i member 3'055362 9/1962 y P i :3: drives the ampoule past the clips so that the needle g g et /5 D enters the patients muscle and then the plunger is amo moved relative to the cylinder to inject the medica- FORElGN PATENTS OR APPLlCATlONS m. 653,356 4/1963 Italy 128/218 F 641,626 6/1962 Italy 128/218 F 4 Clam, 10 Drawmg figures 2 52 j T 32 34a 33 wwa d7- 53 i ii Is. I 526 5 46 2a 5Z5 minimum m4 3.320.542

SHEET 2 0F 3 INTRAMUSCULAR INJECTION DEVICES This application is a division of application Ser. No. 114,493, filed Feb. 11, 1971 now US. Pat. No. 3,735,761.

BACKGROUND OF THE INVENTION tion being performed by collapsing or otherwise actuating the device to preproject the pointed end of the needle through a puncturable wall of the ampoule and then into the patient while reducing the volume of the medicament-containing chamber to express the medicament through the needle and into the patient. Such ampoules are referred to herein by the generic designation, contained-needle type.

Ampoules of this general character are represented, for example, by two series of United States patents granted, respectively, to Russell P. Dunmire and to Stanley J. Sarnoff or Stanley J. Sarnoff et al. The principal ones of those patents to Dunmire are US. Pat. Nos. 2,769,443, 3,094,987, 3,094,988, andv 3,236,237, and the principal ones of those patents to Sarnoff (or Sarnoff et al.) are US. Pat. Nos; 2,704,072, 2,832,339, 3,320,955, and 3,396,726. The devices of those patents of Dunmire and Sarnoff (or Sarnoff et al.) involve a particularly advantageous mode of operation in that the medicament is injected into the patient from the pointed end of the needle as it travelslongitudinally to its maximum depth of penetration, thus distributing the medicament for faster absorption and minimizing discomfort and trauma sometimes occasioned by injecting all of the medicament in one location after the needle has been inserted to the maximum depth. They also greatly reduce the chances for contamination of the medicament or the needle; they requirelittle or no skill on the part of the user, and even make self-injection safe and practical; and they have numerous other inherent advantages which the. art has long recognized.

E However,.none of the devices of that general type has yet been perfected sufficiently for widespread use.

For inspection purposes after filling, it is important that ampoules of the contained-needle types disclosed in the Dunmire and Sarnoff (or Sarnoff et a1.) patents have transparent walls. In order to make the collapsible walls of the ampoules of the Dunmire patents transparent, it has been necessary to mold them from synthetic resin materials-which, because of their possible reactivity with certain medicaments during prolonged periods of storage after filling and before use, have limited the use of such ampoules. Although the components of such devices could be molded of suitably inert natural rubber, that material does not have the transparency required for inspection after filling and, therefore, cannot be used for many applications.

Although the ampoule shell walls that are in contact with a contained medicament during storage of the devices of the Sarnoff (or Sarnoff et al.) patents could be made of transparent, inert, glass tubing and sufficiently inert, molded rubber, end closures for the tubing, so as to avoid the aforementioned inspection problem, the forms of devices shown in those patents have involved various structural, assembly, operational, and/or cost problems that have limited their usefulness and, hence, their commercial acceptance. For example, the puncturable end wall of the devices of those patents of Sarnoff (or Sarnoff et al.) are incapable of sealing against the skin of a patient as required to avoid loss of medicament by seepage between the ampoule end wall and surface of the skin, particularly in the case of such devices designed and used for making relatively shallow subcutaneous injections. When designed as shown in those patents and used as intended for making intramuscular injections, the flow of medicament out of the pointed end of the needle begins as soon as the needle point emerges from the ampoule for penetrating the skin, and such flow continues until the needle has penetrated to its maximum depth in the muscle layer. The result is neither a normal subcutaneous injection nor a normal intramuscular injection but, rather, is a combination of the two that has been acceptable only for very limited injection purposes. The devices of those Dunmire patents, on the other hand, were ideal for making subcutaneous injections, but for the same reason as the devices of the patents of Sarnoff (or Sarnoff et al.), were incapable'of giving a normal intramuscular injection.

Devices have been proposed which are designed for making subcutaneous injections. One such device is shown in US. Pat. No. 3,396,726 to Sarnoff and includes a cylinder which defines a medicamentcontaining ampoule. A piston driven needle is contained in the ampoule and one end of the ampoule is closed by a pierceable diaphragm. The cylinder is only partially filled by the medicament so that the needle may be driven through the diaphragm and into the muscle prior to ejection of the medicament from the needle. However the disclosed method of performing the intramuscular injection according to the Sarnoff patent necessitates the injection of air into the patient. When an injection is performed by skilled personnel, there is little danger if air is injected into the patient. Desirably, however, an injection device should be designed so that an injection may be performed by unskilled personnel such as the patient himself. Unskilled personnel may inject air into a blood vessel and it is therefore important to provide an ampoule and an injection procedure which eliminates this possibility.

As a result of the foregoing problems, and numerous others, prior hypodermic ampoules of the containedneedle type, to which the present invention relates,

have all been subject to severe limitations on their practical utility, and their uses have been restricted accordin gly. The present invention is directed to the provision of a basic ampoule design of the containedneedle type that is adaptable for making intramuscular injections, either of a contained premixed medicament or of two or more separated medicament components that are mixed in the ampoule itself. A major objective is to achieve all of this 1. with a maximum utilization of basic parts of both the ampoules and applicators therefor, 2. with a minimum variation in the techniques of assembling, filling, and using the ampoules, and 3. while overcoming or avoiding the many problems that have heretofore prevented general use of the desirable, contained-needle type of injection device.

SUMMARY OF THE INVENTION I In its simplest form, this invention provides a disposable ampoule of the contained-needle type having a rigid, cylindrical sidewall, an actuating, needle-carrying plunger in one end thereof, and an improved, skinengaging, puncturable, endwall assembly at its opposite end that is suitable for use with an applicator.

This invention provides an intramuscular, disposable, hypodermic ampoule which includes a longer cylindrical sidewall closed at one end by the puncturable diaphragm assembly and closed at its other end by a slidable plunger carrying a needle with a longer cannula. In this case, the cylinder is only partially filled with medicament. Prior to an injection, the plunger is partially depressed by pushing it toward the diaphragm so that the needle projects through and beyond the diaphragm and so that air within the ampoule is expelled prior to initiating the injection. The projecting end of the needle is then pushed through the skin and fascia layers and into the muscle of the patient, and the plunger is completely depressed to inject the medicament as the needle travels further into the muscle. A removable protective shield for the partially advanced needle is preferably provided as an attachment to the puncturable clip and diaphragm assembly and is removed just prior to making the actual injection.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of an ampoule which is adapted to perform an intramuscular injection according to this invention.

FIG.'2 is a cross-sectional view similar to FIG. 1, but showing component parts of the ampoule in positions attained prior to an injection.

FIG. 3 is a cross-sectional view similar to FIG. 2, but showing the ampoule mounted in an applicator and ready for an injection.

FIG. 4 is a cross-sectional view similar to FIG. 3, but showing the ampoule in a position performing an injection.

FIG. 5 is a cross-sectional view of a multichamber hypodermic ampoule according to a further aspect of this invention.

FIGS. 6 and 7 are cross-sectional views illustrating the component parts of the ampoule of FIG. 5 in positions attained at the completion of a mixing operation and after further actuation to ready it for making an injection, respectively.

FIG. 8 is a perspective view of a needle which may be employed in combination with devices according to this invention.

FIG. 9 is a fragmentary perspective view of an ampoule retaining clip provided in the applicators illustrated in FIGS. 3, 4, and 7.

FIG. 10 is a bottom end view of an ampoule mounted in the applicator illustrated in FIGS. 3, 4, and 7.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIGS. 1 through 4, a single chamber ampoule 30 is illustrated. The ampoule 30 is adapted to perform an intramuscular injection and includes a cylinder 31 which is preferably made from glass tubing. One end of the cylinder 31 is provided with a radially extending annular bead 32, and that end of the cylinder is closed by a rubber diaphragm 33 which is pressed against it by a plastic clip 14. The clip 14 is cup-shaped and has an inner annular groove 15 in its cylindrical sidewall which snaps over the bead 32. The clip 14 also includes a bottom wall 140 having a central aperture 14b therethrough.

The diaphragm 13 is preferably molded from rubber and is shaped to function in accordance with the teachings of US. Pat. No. 3,094,988 to Dunmire. It includes an outer, annular portion 16, a thick, elongated, centrally located, needle guiding and liquid sealing gland 17, and a relatively thin, flexible, corrugated, intermediate portion 18 connecting the gland and the outer portion to permit relative axial movement therebetween. The gland extends through the aperture 14b in the clip 14. An axial needle passage 19 may extend into the upper end of the gland from the inside and terminates short of the opposite, lower end of the gland to form a thin, easily puncturable wall 20 closing the bottom of the passage. Alternatively, this needle passage may be omitted when molding the diaphragm and, in effect, be formed by partial piercing of the gland by the needle during assembly of the ampoule.

The other end of the cylinder 31 is closed by a rubber plunger 41 having an enlarged portion 42 which forms a sliding interference fit with the inner sidewall of the cylinder 31. The plunger 41 is provided with an axially extending reduced upper portion 43 which initially extends beyond the cylinder 31. 1

The plunger 41, diaphragm 33, and cylinder 31, together, define a chamber 44 which is partially filled with a liquid medicament. A space Sp (FIG. 1) is provided between the level of the medicament and the initial position of the plunger, and the axial extend of the portion 43 of the plunger 41 corresponds to the axial extent of the space Sp.

Contained within the chamber 44 is a needle 45 which is preferably of the type disclosed in US. Pat. No. 3,173,200 to Dunmire et al. The illustrated circular base 24 at the butt end of the needle 45 is mounted on the plunger 41 so that the needle is in substantial axial alignment with the cylinder 31 and has a pointed end 25 projecting downwardly and received within the axial needle passage 19 of the diaphragm gland 17 in position to be forced through the thin wall 20 of the gland. Mounting of the needle base 24 on the plunger 21 is effected by snapping the peripheral edge of the needle base under an annular lip 26 that is an integral part of the plunger. Flow into the butt end of the needle from the chamber 22 occurs through an opening 27 (see FIG. 8) in the cannula wall adjacent the base 24 of the needle.

A needle guard 46 is removably fixed to the clip 34 and extends axially therefrom. The needle guard 46 is preferably of transparent plastic, is cup-shaped, and has an open mouth which forms an interference fit with an annular, axially projecting shoulder portion 47 of the clip 34. For purposes which will hereinafter become apparent, the guard 46 so provided with a knurled bottom rib 48 and has an axial extent which is greater than the space Sp.

To ensure an intramuscular type injection, the needle 45 must pass through the skin, underlying surface layers of fat, and the fascia layer and enter the muscle prior to medicament flow through the needle. Therefore, the chamber 44 is designed so that its volume is greater than the volume of medicament contained therein. Prior to effecting an injection, the plunger 41 is depressed until the upper end of the portion 43 is level with the top of the cylinder 31, at which point the lower end of the plunger contacts the surface of the liquid in the chamber 44. During this depression operation, the needle 45 pierces the diaphragm 33 and the air or gas in the space Sp is substantially all expelled through the needle. This operation is most conveniently performed by placing the needle guard 46 on a flat surface and pressing the plunger portion 43 downwardly until the ampoule 30 achieves the condition illustrated'in FIG. 2. If desired, the plunger may be depressed in this manner until the appearance of a drop of medicament at the point of the needle (visible through the transparent sidewall of the needle guard 46) indicates the elimination of substantially all air or 41. A preferred method of effecting an injection, however, is to employ an applicator. As fragmentarily shown herein, such an applicator includes a springbiased plunger 50 (FIGS. 3 and 4) mounted within a casing 51. An applicator adapted to perform an intramuscular injection includes an elongated,,metal, bellshaped mouth portion 52 which is provided with diametrically opposed inner spring clips 53 or the like (see FIG. 9) which are spot welded to the inner sidewall of the portion 52. The clips 53 retain the ampoule diaphragm clip 34 in the position illustrated in FIG. 3, so that the partially advanced needle 45 is initially recessed in the applicator. With the needle guard attached, the ampoule 30 is mounted within the applicator by inserting a pair of diametrically opposed lugs 34a provided on the clip 34 into a cooperating pair of slots 52a (FIG. which extend axially through a radially inwardly extending flange 52b. This operation is performed by.grasping the knurled bottom rib 48 on the needle guard 46. The ampoule is pushed upwardly into the casing 51 until the lugs 34a are above the level of the spring clips and is then rotated 90 until the lugs 34a'rest on the clips 53 (see FIG. 3). It is desirable to remove the guard46 after the ampoule 30 is mounted in the applicator to prevent contamination of the needle. The needle guard is removed by pulling one portion of the rib 48 downwardly while pushing a diametrically opposed portion of the rib upwardly since an axial force applied to the rib may disengage the lugs from their retaining spring clips. After the needle guard is removed, the mouth 52 of the applicator is placed against the skin of the patient and the plunger is fired. The applicator spring clips 53 are designed so that they release the ampoule diaphragm clip 34 prior to movement of the plunger 41 relative to the ampoule cylinder 31. To this end, the springs are designed so that the force required to drive the lugs 34a from their retained position is less than the force required to move the plunger 42 relative to the cylinder 31. In this manner, the needle 45 is driven into the muscle M (FIG. 4) prior to injection of the medicament. After the needle 45 enters the muscle, the plunger 41 again moves toward the diaphragm 33 to perform the injection by expressing the medicament through the needle 45 as it is driven further into the muscle M. The injection is complete when the plunger engages the diaphragm.

Referring now to FIGS. 5, 6, and 7 an ampoule is illustrated. The ampoule 180 may be employed to mix liquid and powdered medicaments prior to an injection, and may be employed to effect an intramuscular injection. The ampoule 180 includes a first cylinder 181 which is closed at one end by a rubber plunger 182 and is closed at the other end by a first diaphragm 183. A needle 184 is fixed to the plunger 182 in the same manner previously described, and the diaphragm 183 is slidably received in a second cylinder 185. The second cylinder 185 is closed at its lower end by a second diaphragm 186 and a clip 187 constructed and operating like the previously described similar diaphragm and clip of FIGS. 1-4. A needle guard 188 similar to the needle guard 46 of FIGS. 1 and 2 is removably fixed to the clip 187 and extends axially therefrom as previously described with reference to the latter figures of the drawings.

The first cylinder 181, diaphragm 183, and plunger 182, together, form a first chamber 190 which is evacuated and partially filled with a powdered medicament 191. The second cylinder 185 and diaphragms 183 and 186, together, form a second chamber 192 which is filled with a liquid medicament 193.

The medicaments 191 and 193 are mixed by pushing plunger 182 axially until the needle 184 pierces the diaphragm 183 and provides liquid communication between the chambers 190 and 192. When such communication is established, the diaphragm 183 moves into engagement with the diaphragm 186, and the parts of the ampoule 180 assume the positions illustrated in FIG. 6.

To ensure an intramuscular type injection, the needle 184 must pass through the skin and the surface layers of fat and enter the muscle prior to medicament flow through the needle. Therefore, the chamber 190 is designed so that its vvolume is greater than the total volume of medicament to be contained therein. Thus, as is illustrated in FIG. 6, there is a space Sp between the liquid level and the plunger 182 when the diaphragms 183 and 186 are drawn together. Prior to effecting an injection, the plunger 182 is further depressed until the plunger 182 contacts the surface of the liquid in the chamber 190. This operation projects the needle 184 a predetermined distance beyond the diaphragm 186, which distance substantially corresponds to the normal maximum depth of the muscle beneath the skin of the patient, and air or gas in the chamber 190 is substantially fully expelled in the process as previously described with reference to FIGS. 14.

An injection may then be performed by removing the needle guard 188 and manually applying the ampoule 180 against the skin of the patient so that the needle 184 penetrates the skin and enters the muscle. After this operation, the plunger 182 is completely depressed to inject the medicament into the muscle. Desirably, however, the injection is performed by an applicator which may generally correspond to the applicator 51.

The invention is not restricted to the slavish imitation of each and every detail set forth above. Obviously, ampoule applicators may be provided which change, eliminate or add certain specific details without departing from the scope of the invention.

What is claimed is:

1. In a hypodermic injection assembly:

a. a contained-needle type of hypodermic ampoule comprising a cylinder, a puncturable diaphragm closing and sealing one end of said cylinder, a slidable plunger in the opposite end of said cylinder and spaced from said diaphragm to provide a chamber therebetween, a liquid medicament in said chamber, and a hypodermic needle disposed in said chamber for movement by said plunger to a preinjection position in which a discharge end portion of the needle has pierced and extends beyond said diaphragm in an exposed condition and thereafter to transmit medicament from said chamber into a patient receiving an injection while moving further through said diaphragm, the volume of medicament in said chamber being substantially less than the initial volume of said chamber to permit movement of the plunger to project the needle to said preinjection position before expressing medicament from the chamber through the needle;

b. an applicator for actuating said ampoule to perform an injection after the needle has been projected to its pre-injection position, said applicator comprising a housing having an open end for insertion of said ampoule into the housing with the needle directed axially outwardly relative to said opening until the pointed end of the needle in its preinjection position is within the housing, releasable spring clip means carried by said housing and yieldably restraining said ampoule against reverse movement toward said opening, the restraining force exerted by said spring clip means being less than the force required to move said plunger relative to said cylinder, means operative first to move said ampoule past said spring clip means and toward said housing opening for projecting the needle from the housing substantially for its exposed length in its preinjection position and then for moving said ampoule plunger and needle toward said ampoule diaphragm with a continuing force sufficient to express the medicament from said chamber through said needle and into a patient, said applicator housing including stop means engageable by said ampoule after it has been moved to project the needle into the patient for substantially the exposed length of the needle in its preinjection position, and said ampoule including radially projecting abutments spaced about its periphery for initial restraining engagement by said spring clip means and subsequent positive restraining engagement by said stop means, said spring clip means and said stop means being discontinuous circumferentially of said housing to permit passage of said abutment thereby during insertion of the ampoule and engagement of said abutments thereby after relative rotation of the inserted ampoule about a common axis of said housing and ampoule;

whereby operation of said means to move said ampoule while the open end of the applicator is held against the skin of a patient first moves said ampoule and needle to cause the needle to penetrate into the patient for substantially the exposed length of the needle in said preinjection position and then moves said ampoule plunger toward said ampoule diaphragm for further advancing the needle into the patient while expressing medicament from said ampoule chamber through said needle and into the patient.

2. A hypodermic injection assembly according to claim 1 including a cup-shaped needle guard removably secured to the diaphragm end of said ampoule, said guard having a bottom wall spaced from said diaphragm by a distance exceeding the length of said end portion of the needle in its preinjection position.

3. In a hypodermic injection assembly:

a. a contained-needle type of hypodermic ampoule comprising a cylinder, a puncturable diaphragm closing and sealing one end of said cylinder, a slidable plunger in the opposite end of said cylinder and spaced from said diaphragm to provide a chamber therebetween, a liquid medicament in said chamber, and a hypodermic needle disposed in said chamber for movement by said plunger to a preinjection position in which a discharge end portion of the needle has pierced and extends beyond said diaphragm in an exposed condition and thereafter to transmit medicament from said chamber into a patient receiving an injection while moving further through said diaphragm, the volume of medicament in said chamber being substantially less than the initial volume of said chamber to permit movement of the plunger to project the needle to said preinjection position before expressing medicament from the chamber through the needle;

b. an applicator for actuating said ampoule to perform an injection after the needle has been projected to its preinjection position, said applicator comprising a housing having an open end for insertion of said ampoule into the housing with the needle directed axially outwardly relative to said opening until the pointed end of the needle in its preinjection position is within the housing, detent means yieldably restraining said ampoule against reverse movement toward said opening, means operative first to move said ampoule past said detent means and toward said housing opening for projecting the needle from the housing substantially for its exposed length in its preinjection position and then for moving said ampoule plunger and needle toward said ampoule diaphragm with a continuing force sufficient to express the medicament from said'chamber through said needle and into a patient, said applicator housing including stop means engageable by said ampoule after it has been moved to project the needle into the patient for substantially the exposed length of the needle in its preinjection position, and said ampoule including radially projecting abutments spaced about its periphery for intial restraining engagement by said detent means and subsequent positive restraining engagement by said stop means, said detent means and said stop means being discontinuous circumferentially of said housing to permit passage of said abutments thereby during insertion of the ampoule and engagement of said abutments thereby after relative rotation of the inserted ampoule about a common axis of said housing and ampoule;

whereby operation of said means to move said ampoule while the open end of the applicator is held against the skin of a patient first moves said ampoule and needle to cause the needle to penetrate into the patient for substantially the exposed length of the needle in said preinjection position and then moves said ampoule plunger toward said ampoule diaphragm for further advancing the needle into the patient while expressing 3,820,542 9 10 medicament from said ampoule chamber through said said guard having a bottom wall spaced from said dianeedle and into the patient.

4. A hypodermic injection assembly according to H claim 3 including a cup shaped needle guard remov portion of the needle in its prein ection position. ably secured to the diaphragm end of said ampoule, 5

phragm by a distance exceeding the length of said end 

1. In a hypodermic injection assembly: a. a contained-needle type of hypodermic ampoule comprising a cylinder, a puncturable diaphragm closing and sealing one end of said cylinder, a slidable plunger in the opposite end of said cylinder and spaced from said diaphragm to provide a chamber therebetween, a liquid medicament in said chamber, and a hypodermic needle disposed in said chamber for movement by said plunger to a preinjection position in which a discharge end portion of the needle has pierced and extends beyond said diaphragm in an exposed condition and thereafter to transmit medicament from said chamber into a patient receiving an injection while moving further through said diaphragm, the volume of medicament in said chamber being substantially less than the initial volume of said chamber to permit movement of the plunger to project the needle to said preinjection position before expressing medicament from the chamber through the needle; b. an applicator for actuating said ampoule to perform an injection after the needle has been projected to its preinjection position, said applicator comprising a housing having an open end for insertion of said ampoule into the housing with the needle directed axially outwardly relative to said opening until the pointed end of the needle in its preinjection position is within the housing, releasable spring clip means carried by said housing and yieldably restraining said ampoule against reverse movement toward said opening, the restraining force exerted by said spring clip means being less than the force required to move said plunger relative to said cylinder, means operative first to move said ampoule past said spring clip means and toward said housing opening for projecting the needle from the housing substantially for its exposed length in its Preinjection position and then for moving said ampoule plunger and needle toward said ampoule diaphragm with a continuing force sufficient to express the medicament from said chamber through said needle and into a patient, said applicator housing including stop means engageable by said ampoule after it has been moved to project the needle into the patient for substantially the exposed length of the needle in its preinjection position, and said ampoule including radially projecting abutments spaced about its periphery for initial restraining engagement by said spring clip means and subsequent positive restraining engagement by said stop means, said spring clip means and said stop means being discontinuous circumferentially of said housing to permit passage of said abutment thereby during insertion of the ampoule and engagement of said abutments thereby after relative rotation of the inserted ampoule about a common axis of said housing and ampoule; whereby operation of said means to move said ampoule while the open end of the applicator is held against the skin of a patient first moves said ampoule and needle to cause the needle to penetrate into the patient for substantially the exposed length of the needle in said preinjection position and then moves said ampoule plunger toward said ampoule diaphragm for further advancing the needle into the patient while expressing medicament from said ampoule chamber through said needle and into the patient.
 2. A hypodermic injection assembly according to claim 1 including a cup-shaped needle guard removably secured to the diaphragm end of said ampoule, said guard having a bottom wall spaced from said diaphragm by a distance exceeding the length of said end portion of the needle in its preinjection position.
 3. In a hypodermic injection assembly: a. a contained-needle type of hypodermic ampoule comprising a cylinder, a puncturable diaphragm closing and sealing one end of said cylinder, a slidable plunger in the opposite end of said cylinder and spaced from said diaphragm to provide a chamber therebetween, a liquid medicament in said chamber, and a hypodermic needle disposed in said chamber for movement by said plunger to a preinjection position in which a discharge end portion of the needle has pierced and extends beyond said diaphragm in an exposed condition and thereafter to transmit medicament from said chamber into a patient receiving an injection while moving further through said diaphragm, the volume of medicament in said chamber being substantially less than the initial volume of said chamber to permit movement of the plunger to project the needle to said preinjection position before expressing medicament from the chamber through the needle; b. an applicator for actuating said ampoule to perform an injection after the needle has been projected to its preinjection position, said applicator comprising a housing having an open end for insertion of said ampoule into the housing with the needle directed axially outwardly relative to said opening until the pointed end of the needle in its preinjection position is within the housing, detent means yieldably restraining said ampoule against reverse movement toward said opening, means operative first to move said ampoule past said detent means and toward said housing opening for projecting the needle from the housing substantially for its exposed length in its preinjection position and then for moving said ampoule plunger and needle toward said ampoule diaphragm with a continuing force sufficient to express the medicament from said chamber through said needle and into a patient, said applicator housing including stop means engageable by said ampoule after it has been moved to project the needle into the patient for substantially the exposed length of the needle in its preinjection position, and said ampoule including radially projecting abutments spaced about its periphery for intial restraining engagement by said detent means and subsequent positive restraining engagemenT by said stop means, said detent means and said stop means being discontinuous circumferentially of said housing to permit passage of said abutments thereby during insertion of the ampoule and engagement of said abutments thereby after relative rotation of the inserted ampoule about a common axis of said housing and ampoule; whereby operation of said means to move said ampoule while the open end of the applicator is held against the skin of a patient first moves said ampoule and needle to cause the needle to penetrate into the patient for substantially the exposed length of the needle in said preinjection position and then moves said ampoule plunger toward said ampoule diaphragm for further advancing the needle into the patient while expressing medicament from said ampoule chamber through said needle and into the patient.
 4. A hypodermic injection assembly according to claim 3, including a cup-shaped needle guard removably secured to the diaphragm end of said ampoule, said guard having a bottom wall spaced from said diaphragm by a distance exceeding the length of said end portion of the needle in its preinjection position. 